Neonatal Seizure Etiologies

Primary Causes

• The American College of Radiology guidelines establish that hypoxic-ischemic injury is the dominant etiology of neonatal seizures, representing 46-65% of cases in both term and preterm infants 1, 2
• Intracranial hemorrhage and perinatal ischemic stroke combined account for 10-12% of neonatal seizures, making them the second most common category 1, 2
• Infection, genetic disorders, and malformations of cortical development become more likely causes of neonatal seizures when they occur beyond the seventh day of life 1, 3

Clinical Timing Patterns

• Approximately 90% of infants with hypoxic-ischemic encephalopathy experience seizure onset within the first 2 days after birth, strongly suggesting perinatal asphyxia as the underlying etiology 1, 3, 4
• Late-onset seizures, occurring beyond day 7, are more likely related to infection, genetic disorders, or malformations of cortical development, shifting the differential away from perinatal asphyxia 1, 3

Diagnostic Considerations

• The American College of Radiology guidelines recommend systematic evaluation, including neuroimaging, laboratory studies, and consideration of metabolic and genetic causes, to identify the underlying cause of neonatal seizures, which can be determined in approximately 95% of cases 1, 2, 5